In an image printing apparatus which serves as an information output apparatus for a wordprocessor, personal computer, facsimile apparatus, or the like and is designed to print information such as desired characters and images on a sheet-like printing medium such as a paper sheet or film, a serial printing scheme of printing images while reciprocally scanning in a direction perpendicular to the feed direction of a printing medium such as a paper sheet is widely used owing to its advantages such as low cost and compactness.
One problem that arises when an image is printed at a high speed by using a thermal transfer or sublimation-type image printing apparatus will be described below.
In general, when images are to be printed on the same printing media, each constituted by an image-receiving sheet and ink, which have the same sensitivity, by using a thermal transfer or sublimation-type image printing apparatus, a larger amount of power is required.
This is because in a thermal transfer or sublimation-type image printing apparatus, the energy supplied per unit area of printing medium such as a image receiving sheet for the unit time remains unchanged, and hence a larger amount of power must be supplied in proportion to the image printing amount in printing images on many areas at a high speed.
A power supply unit capable of supplying a large amount of power for the unit time is expensive. This inevitably becomes a factor that increases the cost of an image printing apparatus. For this reason, in the prior art, a high-speed image printing apparatus equipped with such a large-capacity power supply unit has been limited to an image printing apparatus for business use, which gives higher priority to performance than cost to a certain extent and is used to print certificates, seals, and the like.
Recently, with the widespread use of digital cameras, there is an increasing need to print images obtained by digital cameras with ease at a high speed at home. A thermal transfer or sublimation-type image printing apparatus is suitable for such use.
In order to manufacture a thermal transfer or sublimation-type image printing apparatus for which the above requirement for high speed is imposed, the problems associated with manufacturing cost must be solved.